Polyether copolymer, solid polymer electrolyte and battery

ABSTRACT

A solid polymer electrolyte containing a polyether copolymer having a weight-average molecular weight of 10 4  to 10 7  which may optionally be cross-linked and which contains 
     (A) 1 to 99% by mol of a repeating unit derived from a monomer represented by the formula (I):                    
      wherein R 1  represents a divalent organic group, 
     (B) 99 to 1% by mol of a repeating unit derived from ethylene oxide, and 
     (C) 0 to 15% by mol of a repeating unit derived from a monomer having one epoxy group and at least one reactive functional group, an electrolyte salt compound, and a plasticizer has an excellent ionic conductivity.

FIELD OF THE INVENTION

The present invention relates to a polyether copolymer, a solid polymerelectrolyte and a battery. More particularly, it relates to a solidpolymer electrolyte which is suitable as a material for anelectrochemical device such as a battery, a capacitor and a sensor.

RELATED ART

As an electrolyte constituting an electrochemical device such as abattery, a capacitor and a sensor, those in the form of a solution or apaste have hitherto been used in view of the ionic conductivity.However, the following problems are pointed out. That is, there is afear of damage of an apparatus arising due to liquid leakage, andsubminiaturization and thinning of the device are limited because aseparator to be impregnated with an electrolyte solution is required. Tothe contrary, a solid electrolyte such as inorganic crystallinesubstance, inorganic glass and organic polymer substance is suggested.The organic polymer substance is generally superior in processabilityand moldability and the resulting solid electrolyte has good flexibilityand bending processability and, furthermore, the design freedom of thedevice to be applied is high and, therefore, the development isexpected. However, the organic polymer substance is inferior in ionicconductivity to other materials at present.

Extensive researches have been carried out on solid polymer electrolytessince the finding of ionic conductivity in a system of ethylene oxidehomopolymer and alkali metal ions. As a result, polyethers such aspolyethylene oxide are now considered to be most promising as polymermatrices in view of their high mobilities and solubilities of metalcations. It has been predicted that migration of ions occurs inamorphous regions rather than crystalline regions of such polymers.Since then, copolymerization of polyethylene oxide with various epoxideshas been carried out in order to decrease the crystallinity ofpolyethylene oxide. Japanese Patent Kokoku Publication No. 249361/1987discloses solid electrolytes comprising copolymers of ethylene oxide andpropylene oxide, and U.S. Pat. No. 4,818,644 discloses solidelectrolytes comprising copolymers of ethylene oxide and methyl glycidylether. Their ionic conductivities were not, however, entirelysatisfactory in either case.

Although Japanese Patent Kokai Publication No. 235957/1990 filed by thepresent applicant proposes an attempt in which particular alkali metalsalts are contained in mixtures of epichlorohydrin-ethylene oxidecopolymers and low molecular weight polyethylene glycol derivatives tobe used as solid polymer electrolytes, a practically adequate value ofconductivity could not been achieved.

Furthermore, Japanese Patent Kokai Publication Nos. 223842/1994 and295713/1996 describe solid electrolytes comprising copolymers havingcarbonate groups on the side chains. The backbone of these copolymers,however, does not have a polyether structure, but has a polyolefinstructure which has a poor mobility and a low conductivity.

SUMMARY OF THE INVENTION

An object of the present invention provides a solid electrolyte which issuperior mechanical properties and ionic conductivity.

The present invention provides a polyether copolymer having aweight-average molecular weight of 10⁴ to 10⁷ which may optionally becross-linked and which comprises:

(A) 1 to 99% by mol of a repeating unit derived from a monomerrepresented by the formula (I):

 wherein R¹ represents a divalent organic group,

(B) 99 to 1% by mol of a repeating unit derived from a monomerrepresented by the formula (II):

 and

(C) 0 to 15% by mol of a repeating unit derived from a monomer havingone epoxy group and at least one reactive functional group.

The present invention also provides a solid polymer electrolytecomprising:

(1) the above polyether copolymer,

(2) an electrolyte salt compound, and

(3) if necessary, a plasticizer selected from the group consisting of anaprotic organic solvent, and a derivative or metal salt of a linear orbranched polyalkylene glycol having a number-average molecular weight of200 to 5,000 or a metal salt of said derivative.

The present invention further provides a battery comprising the abovesolid polymer electrolyte.

A crosslinked material of the polyether copolymer is used when the shapestability at high temperature is required.

When the plasticizer is blended with the solid polymer electrolyte, thecrystallization of the polymer is inhibited and the glass transitiontemperature is lowered and a large amount of an amorphous phase isformed even at low temperature and, therefore, the ionic conductivity isimproved. It has been also found that, when the solid polymerelectrolyte of the present invention is used, a high-performance batteryhaving small internal resistance can be obtained. The solid polymerelectrolyte of the present invention may be in the form of a gel. Theterm “gel” used herein means a polymer swollen with a solvent.

DETAILED DESCRIPTION OF THE INVENTION

The repeating unit (C) may be derived from a monomer of the formula(III):

wherein R² represents a reactive functional group-containing group.

The polyether polymer of the present invention comprises

(A) a repeating unit derived from a monomer (I):

wherein R¹ is a divalent group, and

(B) a repeating unit derived from a monomer (II):

 CH₂—CH₂—O  (II′)

In the polyether copolymer of the present invention, the divalent groupof R¹ group in the formula (I) is preferably

—CH₂—O—(CHA¹—CHA²—O)_(n)—CH₂—,

—CH₂—O—(CH₂)_(n)—,

—CH₂—O—(O)C—(CH₂)_(n)—,

—(CH₂)_(m)—CO₂—(CH₂)_(n)—, or

—(CH₂)_(m)—O—CO₂—(CH₂)_(n)—

wherein each of A¹ and A² is hydrogen or a methyl group, n is the numberof 0 to 12,

and m is the number of 0 to 6.

More preferably, the R¹ group is

—CH₂—O—(CHA¹—CHA²—O)_(n)—CH₂—,

—CH₂—O—(CH₂)_(n)—, or

—CH₂—O—(O)C—(CH₂)_(n)—

wherein each of A¹ and A² is hydrogen or a methyl group, and n is thenumber of 0 to 6.

The polyether copolymer optionally comprises (C) a repeating unitderived from a monomer having one epoxy group and at least one reactivefunctional group. A crosslinked material can be derived from thepolyether copolymer having the repeating unit (C) by utilizing thereactivity of the reactive functional group.

The copolymer used in the present invention may be crosslinked or notcrosslinked. Examples of a crosslinking agent for crosslinking a binarycopolymer having the repeating unit (I′) and the repeating unit (II′)specifically include isocyanate compounds such as 2,4-tolylenediisocyanate, 2,6-tolylene diisocyanate, 4,4-diphenylmethanediisocyanate and hexamethylene diisocyanate.

The repeating unit (C) derived from a monomer of the formula (III) isrepresented by the formula (III′):

wherein R² represent a reactive functional group-containing group.

The reactive functional group in the repeating unit (C) is preferably(a) a reactive silicon group, (b) an epoxy group, (c) an ethylenicallyunsaturated group, or (d) a halogen atom.

The polymerization method of the polyether copolymer, which may have acrosslinkable side chain, of the present invention is the polymerizationmethod wherein a copolymer is obtained by a ring opening reaction ofethylene oxide portion and can be conducted in the same manner as thatdescribed in Japanese Patent Kokai Publication Nos. 154736/1988 and169823/1987 filed by the present applicant.

The polymerization reaction can be conducted as follows. That is, thepolyether copolymer can be obtained by reacting the respective monomersat the reaction temperature of 10 to 80° C. under stirring, using acatalyst mainly containing an organoaluminum, a catalyst mainlycontaining an organozinc, an organotin-phosphate ester condensatecatalyst and the like as a ring opening polymerization catalyst in thepresence or absence of a solvent. Among of them, the organotin-phosphateester condensate catalyst is particularly preferable in view of thepolymerization degree, or properties of the resulting copolymer and thelike. In the polymerization reaction, the reactive functional group doesnot react so that a copolymer having the reaction functional group isobtained. When an oxirane compound having epoxy groups at only the bothends is used, an only epoxy group containing no substituent such as nomethyl group is used for polymerization and an epoxy group containing amethyl group remains in the polymer without any reaction.

In the polyether copolymer of the present invention, the content of therepeating unit (A) is from 1 to 99% by mol, e.g. from 3 to 99% by mol,particularly from 10 to 95% by mol, and especially from 10 to 80% bymol; the content of the repeating unit (B) is from 99 to 1% by mol, e.g.from 95 to 1% by mol, particularly from 90 to 5% by mol, andspecifically from 80 to 5% by mol; and the content of the repeating unit(C) is from 0 to 15% by mol, e.g. 0 to 10% by mol, preferably from 0 to5% by mol, and particularly 0.001 to 5% by mol. When the content of therepeating unit (B) exceeds 99% by mol, an increase in glass transitiontemperature and crystallization of the oxyethylene chain arise, whichresults in drastic deterioration of the ionic conductivity of the solidelectrolyte. It is generally known that the ionic conductivity isimproved by the decrease of the crystallizability of polyethylene oxide.It has been found that, in case of the polyether copolymer of thepresent invention, the effect for improvement of the ionic conductivityis remarkably large.

With respect to the molecular weight of the polyether copolymer, theweight-average molecular weight is suitable within the range from 10⁴ to10⁷, and preferably from 10⁴ to 5×10⁶, so as to give excellentprocessability, moldability, mechanical strength and flexibility. Morepreferably it is from 5×10⁴ to 5×10⁶, particularly from 10⁵ to 5×10⁶.

In the present invention, a glass transition temperature of thepolyether copolymer is preferably not more than −40° C., and a fusionheat of the polyether copolymer is preferably not more than 90 J/g. Ifthe glass transition temperature and the fusion heat exceed the abovevalues, a decrease of ionic conductivity may arise. The glass transitiontemperature and the fusion heat of the polyether copolymer are measuredby a differential scanning calorimeter (DSC).

The polyether copolymer of the present invention may be any copolymertype such as a block copolymer and a random copolymer, but the randomcopolymer is preferable because the effect for reduction of thecrystallizability of polyethylene oxide is large. The polyethercopolymer of the present invention is a polyether copolymer having aside chain containing two oligooxyethylene groups and, if necessary, aside chain containing a crosslinkable reactive functional group. Thepolyether copolymer of the present invention is a copolymer formed fromat least two monomers.

The monomer having a reactive silicon group, which constitutes therepeating unit (C), is preferably represented by the formula (III-a):

wherein R³ is a reactive silicon-containing group.

The reactive silicon group-containing monomer represented by the formula(III-a) is preferably a compound represented by the formula (III-a-1) or(III-a-2).

In the formulas (III-a-1) and (III-a-2), R⁴, R⁵ and R⁶ may be the sameor different, but at least one of them represents an alkoxy group andthe remainder represent an alkyl group; and k represents 1 to 6.

Examples of the monomer represented by the formula (III-a-1) include2-glycidoxyethyltrimethoxysilane,3-glycidoxypropylmethyldimethoxysilane,3-glycidoxypropyltrimethoxysilane and4-glycidoxybutylmethyltrimethoxysilane.

Examples of the monomer represented by the formula (III-a-2) include3-(1,2-epoxy)propyltrimethoxysilane, 4-(1,2-epoxy)butyltrimethoxysilaneand 5-(1,2-epoxy)pentyltrimethoxysilane.

1-(3,4-epoxycyclohexyl)methylmethyldimethoxysilane and2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane can be used in addition tothe monomers (III-a-1) and (III-a-2).

Among them, 3-glycidoxypropyltrimethoxysilane,3-glycidoxypropylmethyldimethoxysilane and4-(1,2-epoxy)butyltrimethoxysilane are particularly preferable.

The monomer having two epoxy groups, which constitutes the repeatingunit (C), is preferably represented by the formula (III-b):

wherein R⁷ is a divalent organic group. The monomer having two epoxygroups preferably has epoxy groups at the both ends. R⁷ is preferably anorganic group comprising elements selected from hydrogen, carbon andoxygen.

It is preferable that the group R⁷ in the formula (III-b) is

—CH₂—O—(CHA¹—CHA²—O)_(m)—CH₂—,

—(CH₂)_(m)—, or

—CH₂O—Ph—OCH₂—

wherein A¹ and A² represent hydrogen or a methyl group; Ph represents aphenylene group; and m represents a numeral of 0 to 12.

The monomer having two epoxy groups is preferably a compound representedby the following formula (III-b-1), (III-b-2) or (III-b-3):

In the above formulas (III-b-1), (III-b-2) and (III-b-3), A¹ and A²represent a hydrogen atom or a methyl group; and m represents a numeralof 0 to 12.

Examples of the monomer represented by the formula (III-b-1) include2,3-epoxypropyl-2′,3′-epoxy-2′-methyl propyl ether, ethyleneglycol-2,3-epoxypropyl-2′,3′-epoxy-2′-methyl propyl ether, anddiethylene glycol-2,3-epoxypropyl-2′,3′-epoxy-2′-methyl propyl ether.

Examples of the monomer represented by the formula (III-b-2) include2-methyl-1,2,3,4-diepoxybutane, 2-methyl-1,2,4,5-diepoxypenatane, and2-methyl-1,2,5,6-diepoxyhexane.

Examples of the monomer represented by the formula (III-b-3) includehydroquinone-2,3-epoxypropyl-2′,3′-epoxy-2′-methyl propyl ether, andcatechol-2,3-epoxypropyl-2′,3′-epoxy-2′-methyl propyl ether.

Among them, 2,3-epoxypropyl-2′,3′-epoxy-2′-methyl propyl ether andethylene glycol-2,3-epoxypropyl-2′,3′-epoxy-2′-methyl propyl ether areparticularly preferable.

The monomer having the ethylenically unsaturated group, whichconstitutes the repeating unit (C), is preferably represented by theformula (III-c):

wherein R⁸ is a group having an ethylenically unsaturated group.

As the ethylenically unsaturated group-containing monomer, there can beused allyl glycidyl ether, 4-vinylcyclohexyl glycidyl ether, α-terpinylglycidyl ether, cyclohexenylmethyl glycidyl ether, p-vinylbenzylglycidyl ether, allylphenyl glycidyl ether, vinyl glycidyl ether,3,4-epoxy-1-butene, 3,4-epoxy-1-pentene, 4,5-epoxy-2-pentene,1,2-epoxy-5,9-cyclododecadiene, 3,4-epoxy-1-vinylcyclohexene,1,2-epoxy-5-cyclooctene, glycidyl acrylate, glycidyl methacrylate,glycidyl sorbate, glycidyl cinnamate, glycidyl crotonate andglycidyl-4-hexenoate. Allyl glycidyl ether, glycidyl acrylate andglycidyl methacrylate are preferable.

The monomer (C) having a halogen atom is preferably represented by theformula (III-d):

wherein R⁹ is a group having at least one halogen atom. R⁹ may be, e.g.an alkyl group substituted with a halogen atom, for example, a C₁₋₆alkyl group.

Examples of the monomer having a halogen atom include:

wherein X is a halogen atom, particularly a bromine atom (Br) or aiodine atom (I). Examples of the monomer having a halogen atom includeepibromohydrin and epiiodohydrin.

As the crosslinking method of the copolymer wherein the reactivefunctional group is a reactive silicon group, the crosslinking can beconducted by the reaction between the reactive silicon group and water.In order to increase the reactivity, there may be used, as a catalyst,organometal compounds, for example, tin compounds such as dibutyltindilaurate and dibutyltin maleate; titanium compounds such as tetrabutyltitanate and tetrapropyl titanate; aluminum compounds such as aluminumtrisacetyl acetonate and aluminum trisethyl acetoacetate; or aminecompounds such as butylamine and octylamine.

As the crosslinking method of the copolymer wherein the reactivefunctional group is an epoxy group, polyamines, acid anhydrides and thelike can be used.

Examples of the polyamines include aliphatic polyamines such asdiethylenetriamine and dipropylenetriamine; and aromatic polyamines suchas 4,4′-diaminodiphenyl ether, diaminodiphenyl sulfone,m-phenylenediamine and xylylenediamine. The amount of the polyaminevaries depending on the type of the polyamine, but is normally withinthe range from 0.1 to 10% by weight based on the whole compositionexcluding a plasticizer (that is, a composition excluding a plasticizerfrom a solid electrolyte).

Examples of the acid anhydrides includes maleic anhydride, phthalicanhydride, methylhexahydrophthalic anhydride, tetramethylenemaleicanhydride and tetrahydrophthalic anhydride. The amount of the acidanhydrides varies depending on the type of the acid anhydride, but isnormally within the range from 0.1 to 10% by weight based on the wholecomposition excluding a plasticizer. In the crosslinking, an acceleratorcan be used. In the crosslinking reaction of polyamines, the acceleratorinclude phenol, cresol and resorcin. In the crosslinking reaction of theacid anhydride, the accelerator include benzyldimethylamine,2-(dimethylaminoethyl)phenol and dimethylaniline. The amount of theaccelerator varies depending on the type of the accelerator, but isnormally within the range from 0.1 to 10% by weight based on thecrosslinking agent.

In the crosslinking method of the copolymer wherein the reactivefunctional group is an ethylenically unsaturated group, a radicalinitiator selected from an organic peroxide and an azo compound, oractive energy ray such as ultraviolet ray and electron ray can be used.It is also possible to use a crosslinking agent having a siliconhydride.

As the organic peroxide, there can be used those which are normally usedin the crosslinking, such as a ketone peroxide, a peroxy ketal, ahydroperoxide, a dialkyl peroxide, a diacyl peroxide and a peroxy ester.Specific examples of the organic peroxide include1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, di-t-butyl peroxide,t-butylcumyl peroxide, dicumyl peroxide,2,5-dimethyl-2,5-di(t-butylperoxy)hexane and benzoylperoxide. The amountof the organic peroxide varies depending on the type of the organicperoxide, but it is normally within the range from 0.1 to 10% by weightbased on the whole composition excluding a plasticizer.

As the azo compound, there can be used those which are normally used inthe crosslinking, such as an azonitrile compound, an azoamide compoundand an azoamidine compound. Specific examples of the azo compoundinclude 2,2′-azobisisobutyronitrile, 2,2′-azobis(2-methylbutyronitrile),2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile),2,2-azobis(2-methyl-N-phenylpropionamidine)dihydrochloride,2,2′-azobis[2-(2-imidazolin-2-yl)propane],2,2′-azobis[2-methyl-N-(2-hydroxyethyl)propionamide],2,2′-azobis(2-methylpropane) and2,2′-azobis[2-(hydroxymethyl)propionitrile]. The amount of the azocompound varies depending on the type of the azo compound, but isnormally within the range from 0.1 to 10% by weight based on the wholecomposition excluding a plasticizer.

In the crosslinking due to radiation of activated energy ray such asultraviolet ray, glycidyl acrylate ester, glycidyl methacrylate esterand glycidyl cinnamate ester are particularly preferable among themonomer component represented by the formula (III-c). Furthermore, asthe auxiliary sensitizer, there can be optionally used acetophenonessuch as diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-oneand phenylketone; benzoin ethers such as benzoin and benzoin methylether; benzophenones such as benzophenone and 4-phenylbenzophenone;thioxanthones such as 2-isopropylthioxanthone and2,4-dimethylthioxanthone; azides such as 3-sulfonylazidobenzoic acid and4-sulfonylazidobenzoic acid.

As a crosslinking aid, there can be optionally used ethylene glycoldiacrylate, ethylene glycol dimethacrylate, oligoethylene glycoldiacrylate, oligoethylene glycol dimethacrylate, allyl methacrylate,allyl acrylate, diallyl maleate, triallyl isocyanurate, maleimide,phenylmaleimide and maleic anhydride.

As the compound having a silicon hydride group, which is used forcrosslinking the ethylenically unsaturated group, a compound having atleast two silicon hydride groups can be used. Particularly, apolysiloxane compound or a polysilane compound is preferable.

Examples of the polysiloxane compound include a linear polysiloxanecompound represented by the formula (a-1) or (a-2), or a cyclicpolysiloxane compound represented by the formula (a-3).

In the formulas (a-1) to (a-3), R¹⁰, R¹¹, R¹², R¹³, R¹⁴, R¹⁵, R¹⁶, R¹⁷and R¹⁸ respectively represent a hydrogen atom or an alkyl or alkoxygroup having 1 to 12 carbon atoms; and n≧2, m≧0, 2≦m+n≦300. As the alkylgroup, a lower alkyl group such as a methyl group and an ethyl group ispreferable. As the alkoxy group, a lower alkoxy group such as a methoxygroup and an ethoxy group is preferable.

As the polysilane compound, a linear polysilane compound represented bythe formula (b-1) can be used.

In the formula (b-1), R¹⁹, R²⁰, R²¹, R²² and R²³ respectively representa hydrogen atom or an alkyl or alkoxy group having 1 to 12 carbon atoms;and n≧2, m≧0, 2≦m+n≦100.

Examples of the catalyst of the hydrosilylation reaction includetransition metals such as palladium and platinum or a compound orcomplex thereof. Furthermore, peroxide, amine and phosphine can also beused. The most popular catalyst includesdichlorobis(acetonitrile)palladium(II),chlorotris(triphenyl-phosphine)rhodium(I) and chloroplatinic acid.

In the crosslinking method of the copolymer containing a halogen atom(e.g. a bromine atom or a iodine atom), for example, a crosslinkingagent such as polyamines, mercaptoimidazolines, mercaptopyrimidines,thioureas and polymercaptanes can be used. Examples of the polyaminesinclude triethylenetetramine and hexamethylenediamine. Examples of themercaptoimidazolines include 2-mercaptoimidazoline and4-methyl-2-mercaptoimidazoline. Examples of the mercaptopyrimidinesinclude 2-mercaptopyrimidine, 4,6-dimethyl-2-mercaptopyrimidine.Examples of the thioureas include ethylene thiourea and dibutylthiourea. Examples of the polymercaptanes include2-dibutylamino-4,6-dimethylcapto-s-triazine,2-phenylamino-4,6-dimercaptotriazine. The amount of the crosslinkingagent varies depending on the type of the crosslinking agent, but isnormally within the range from 0.1 to 30% by weight based on the wholecomposition excluding a plasticizer.

Furthermore, it is effective to add a metal compound as an acid acceptorto the solid polymer electrolyte in view of the thermal stability of thehalogen-containing polymer. Examples of the metal oxide as the acidacceptor include oxide, hydroxide, carbonate salt, carboxylate salt,silicate salt, borate salt and phosphite salt of Group II metal of theperiodic table; and oxide, basic carbonate salt, basic carboxylate salt,basic phosphite salt, basic sulfite salt and tribasic sulfate salt ofGroup VIa metal of the periodic table. Specific examples thereof includemagnesia, magnesium hydroxide, magnesium carbonate, calcium silicate,calcium stearate, read lead and tin stearate. The amount of the metalcompound as the above acid acceptor varies depending on the typethereof, but is normally within the range from 0.1 to 30% by weightbased on the whole composition excluding a plasticizer.

The electrolyte salt compound used in the present invention ispreferably soluble in a mixture comprising a polyether copolymer or acrosslinked material of the copolymer and a plasticizer. In the presentinvention, the following salt compounds are preferably used.

That is, examples thereof include a compound composed of a cationselected from a metal cation, ammonium ion, amidinium ion and guanidiumion, and an anion selected from chloride ion, bromide ion, iodide ion,perchlorate ion, thiocyanate ion, tetrafluoroborate ion, nitrate ion,AsF₆ ⁻, PF₆ ⁻, stearylsulfonate ion, octylsulfonate ion,dodecylbenzenesulfonate ion, naphthalenesufonate ion,dodecylnaphthalenesulfonate ion, 7,7,8,8-tetracyano-p-quinodimethaneion, X¹SO₃ ⁻, [(X¹SO₂)(X²SO₂)N]⁻, [(X¹SO₂)(X²SO₂)(X³SO₂)C]⁻ and[(X¹SO₂)(X²SO₂)YC]⁻, wherein X¹, X², X³ and Y respectively represent anelectron attractive group. Preferably, X¹, X² and X³ independentlyrepresent a perfluoroalkyl having 1 to 6 carbon atoms or a perfluoroarylgroup and Y represents a nitro group, a nitroso group, a carbonyl group,a carboxyl group or a cyano group. X¹, X² and X³ may be the same ordifferent. As the metal cation, a cation of a transition metal can beused. Preferably, a cation of a metal selected from Mn, Fe, Co, Ni, Cu,Zn and Ag metals is used. When using a cation of a metal selected fromLi, Na, K, Rb, Cs, Mg, Ca and Ba metals, good results are also obtained.Two or more compounds described above may be used as the electrolytesalt compound.

In the present invention, the amount of the electrolyte salt compound isso that a numeral value of a molar ratio of the number of moles of theelectrolyte salt compound to the total number of moles of oxyethyleneunits (the total number of moles of oxyethylene units included in a mainchain and side chain of the polyether copolymer) is preferably withinthe range from 0.0001 to 5, more preferably from 0.001 to 0.5. When thisvalue exceeds 5, the processability and moldability, the mechanicalstrength and flexibility of the resulting solid electrolyte may bedeteriorated and the ionic conductivity may decrease.

The plasticizer is an aprotic organic solvent, or a derivative or ametal salt of a linear or branched polyalkylene glycol having anumber-average molecular weight of 200 to 5,000, or a metal salt of thederivative.

As the aprotic organic solvent, aprotic ethers and esters arepreferable. Specific examples include propylene carbonate,γ-butyrolactone, butylene carbonate, ethylene carbonate, dimethylcarbonate, ethylmethyl carbonate, diethyl carbonate,1,2-dimethoxyethane, 1,2-dimethoxypropane, 3-methyl-2-oxyazolidone,tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane,4,4-methyl-1,3-dioxolane, tert-butyl ether, iso-butylether,1,2-ethoxymethoxyethane, ethylene glycol dimethyl ether, ethylene glycoldiethyl ether, triethylene glycol dimethyl ether, triethylene glycoldiethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycoldiethyl ether, ethylene glyme, ethylene diglyme, methyl tetraglyme,methyl triglyme, methyl diglyme, methyl formate, methyl acetate andmethyl propionate and a mixture of two or more of them may be used.Particularly, propylene carbonate, γ-butyrolactone, butylene carbonateand 3-methyl-2-oxyazoline are preferable. Triethylene glycol dimethylether, triethylene glycol diethyl ether, tetraethylene glycol dimethylether and tetraethylene glycol diethyl ether are also particularlypreferable organic solvents.

The derivative or metal salt of the linear or branched polyalkyleneglycol or the metal salt of the derivative can be obtained from apolyalkylene glycol having a number-average molecular weight of 200 to5,000. Examples of the polyalkylene glycol include polyethylene glycolor polypropylene glycol, and examples of the derivative thereof includean ester derivative or ether derivative having an alkyl group having 1to 8 carbon atoms and an alkenyl group having 3 to 8 carbon atoms.

Among the derivatives, examples of the ether derivative include dietherssuch as dimethyl ether, diethyl ether, dipropyl ether and diallyl ether,and examples of the ester derivative include diesters such aspolyalkylene glycol dimethacrylate ester (e.g. polyethylene glycoldimethacrylate ester), polyalkylene glycol diacetate ester (e.g.polyethylene glycol diacetate ester), and polyalkylene glycol diacrylateester (e.g. polyethylene glycol diacrylate ester).

Examples of the metal salt include a sodium, lithium and dialkylaluminum salt of polyalkylene glycol.

Examples of the metal salt of the derivative include sodium, lithium anddialkylaluminum salts (e.g. dioctylaluminum salt) of monoethers such asmonomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether,monohexyl ether, mono-2-ethyl-hexyl ether and monoallyl ether; andmonoesters such as monoacetate ester, monoacrylate ester andmonomethacrylate ester. Examples of the metal salt of polyalkyleneglycol derivative include dioctylaluminum salt of polyethylene glycolmonomethyl ether, dioctylaluminum salt of polyethylene glycol monoethylether and dioctylaluminum salt of polyethylene glycol monoallyl ether.

The number-average molecular weight of the polyalkylene glycol used ismore preferably within the range from 200 to 2,000.

The formulating proportion of the plasticizer is optionally selected,but is from 0 to 2,000 parts by weight, preferably 1 to 2,000 parts byweight, e.g. 10 to 1,000 parts by weight, particularly from 10 to 500parts by weight, based on 100 parts by weight of the polyethercopolymer.

When the flame retardancy is required in using the solid polymerelectrolyte, a flame retardant can be used. That is, an effective amountof those selected from a halide (such as a brominated epoxy compound,tetrabromobisphenol A and chlorinated paraffin), antimony trioxide,antimony pentaoxide, aluminum hydroxide, magnesium hydroxide, phosphateester, polyphosphate salt and zinc borate as a flame retardant can beadded.

The method for production of the solid polymer electrolyte of thepresent invention is not specifically limited, but the respectivecomponents may be mechanically mixed, normally. In case of themulticomponent-copolymer requiring the crosslinking, it is produced by amethod such as mechanically mixing the respective components, followedby crosslinking. Alternatively, after crosslinking, the crosslinkedcopolymer may be impregnated by immersing in a plasticizer for a longtime. As means for mechanically mixing, various kneaders, open rolls,extruders and the like can be optionally used.

In case that the reactive functional group is a reactive silicon group,the amount of water used in the crosslinking reaction is notspecifically limited because the crosslinking reaction easily occurseven in the presence of moisture in the atmosphere. The crosslinking canalso be conducted by passing through a cold water or hot water bath fora short time, or exposing to a steam atmosphere.

In case of the copolymer wherein the reactive functional group is anepoxy group-containing group, when using a polyamine or an acidanhydride, the crosslinking reaction is completed at the temperature of10 to 200° C. within 10 minutes to 20 hours.

In case of the copolymer wherein the reactive functional group is anethylenically unsaturated group, when using a radical initiator, thecrosslinking reaction is completed at the temperature of 10 to 200° C.within 1 minutes to 20 hours. Furthermore, when using energy ray such asultraviolet ray, a sensitizer is normally used. The crosslinkingreaction is normally completed at the temperature of 10 to 150° C.within 0.1 seconds to 1 hour. In case of the crosslinking agent having asilicon hydride, the crosslinking reaction is completed at thetemperature of 10 to 180° C. within 10 minutes to 10 hours.

The method of mixing the electrolyte salt compound and plasticizer withthe polyether copolymer is not specifically limited, but examplesthereof include a method of impregnating by immersing the polyethercopolymer in an organic solvent containing the electrolyte salt compoundand plasticizer for a long time, a method of mechanically mixing theelectrolyte salt compound and plasticizer with the polyether copolymer,a method of dissolving the polyether copolymer and the electrolyte saltcompound in the plasticizer, followed by mixing or a method ofdissolving the polyether copolymer once in the other organic solvent,followed by mixing the plasticizer. When producing by using the organicsolvent, various polar solvents such as tetrahydrofuran, acetoneacetonitrile, dimethylformamide, dimethyl sulfoxide, dioxane, methylethyl ketone and methyl isobutyl ketone, may be used alone or incombination thereof.

The solid polymer electrolyte shown in the present invention is superiorin mechanical strength and flexibility, and a large area thin-filmshaped solid electrolyte can be easily obtained by utilizing theproperties. For example, it is possible to make a battery comprising thesolid polymer electrolyte of the present invention. In this case,examples of the positive electrode material include lithium-manganesedouble oxide, lithium cobaltate, vanadium pentaoxide, polyacetylene,polyacene, polypyrene, polyaniline, polyphenylene, polyphenylenesulfide, polyphenylene oxide, polypyrrole, polyfuran and polyazulene.Examples of the negative electrode material include an interlaminarcompound prepared by occlusion of lithium between graphite or carbonlayers, a lithium metal and a lithium-lead alloy. By utilizing the highion conductivity, the solid polymer electrolyte can also be used as adiaphragm of an ion electrode of the cation such as alkaline metal ion,Cu ion, Ca ion and Mg ion. The solid polymer electrolyte of the presentinvention is especially suitable as a material for electrochemicaldevice (e.g. a battery, a capacitor and a sensor).

PREFERRED EMBODIMENTS OF THE INVENTION

The following Examples further illustrate the present invention indetail.

In the following Examples, a monomer (glycidyl ether compound) of theformula (1) is as follows:

The monomer used in this example was synthesized in two steps.

SYNTHESIS EXAMPLE 1 Synthesis of Monomer

Step 1

Into a 500 ml reaction vessel equipped with a Dean-Stark trap, a Dimrothcondenser and a magnetic stirrer bar, 133 g (1 mol) of 1-allylglycerin,300 ml of dimethyl carbonate, and 3 g (0.075 mol) of sodium hydroxidepellet were charged. The mixture was heated to 60° C., stirred for 30minutes, and the temperature was then raised to 90° C. to remove amixture of dimethyl carbonate and the methanol out of the reactionsystem until any distillate has been no longer distilled. The reactionmixture was cooled, and tetrahydrofuran was added thereto. Afterfiltering off the precipitate, the filtrate was concentrated underreduced pressure to give 150.3 g (95% yield) of4-allyloxymethyl-1,3-dioxolan-2-one.

Step 2

Into a 1 L reaction vessel, 78.3 g (0.5 mol) of4-allyloxymethyl-1,3-dioxolan-2-one obtained in Step 1 and 500 ml ofdichloromethane were charged and cooled to 0° C. Into this mixture, 183g (0.75 mol) of m-chloroperbenzoic acid was added in small portions.After completing the addition, the reaction temperature was raised toroom temperature and the reaction mixture was stirred overnight. Aftercompletion of the reaction, the salt was filtered off, and the filtratewas cooled to 0° C. and stirred for 30 minutes while adding 300 ml of a10% aqueous solution of sodium thiosulfate in small portions. Afterseparating an aqueous layer, an organic layer was washed with asaturated aqueous solution of sodium hydrogen carbonate, dried overanhydrous magnesium sulfate, filtered, and concentrated under reducedpressure. The crude product was subjected to a silica-gel chromatographyand then distilled to give 51.7 g (60% yield) of propylene carbonateglycidyl ether, bp. 154/0.4 mmHg.

The structure of the product obtained was confirmed by ¹H NMR.Conditions for ¹H NMR measurement: solvent, C₆D₆; internal standard,TMS; measurement temperature, 30° C. Results of ¹H NMR measurement: thepeaks corresponding to the following structure were observed. δ: 1.9-2.1(2H, m, a), δ: 2.6 (1H, m, b), δ: 3.5 (1H, m, c), δ: 2.7-3.8 (6H, m, d).

SYNTHESIS EXAMPLE 2 Preparation of Catalyst

Into a 3-necked flask equipped with a stirrer, a thermometer and adistillation apparatus, 10 g of tributyltin chloride and 35 g oftributyl phosphate were charged and heated at 250° C. for 20 minuteswith stirring under nitrogen stream while evaporating the distillate togive a solid condensate as a residue. Hereinafter, theorganotin/phosphoric acid ester condensate was used as a catalyst forpolymerization.

The composition of the polyether copolymer in terms of monomers wasdetermined on the basis of the ¹H NMR spectrum. For determination ofmolecular weight of the polyether copolymer, a gel permeationchromatography measurement was conducted and the molecular weight wascalculated in terms of standard polystyrenes. The gel permeationchromatography measurement was performed at 60° C. using a measuringapparatus RID-6A (Shimadzu Co.), Shodex KD-807, KD-806, KD-806M andKD-803 columns (Showa Denko K.K.), and DMF as a solvent. A glasstransition temperature and a heat of fusion were determined using adifferential scanning calorimeter DSC 8230B (Rigaku Denki K.K.) undernitrogen atmosphere over a temperature range from −100 to 80° C. at arate of temperature rise of 10° C./min. Determination of electricconductivity δ was made on a film which had been vacuum-dried at 20° C.under 1 mmHg for 72 hours by clamping it between platinum electrodes andapplying an alternating current (voltage, 0.5 V; frequency range, 5 Hzto 1 MHz) in order to calculate the electric conductivity according to acomplex impedance method.

EXAMPLE 1

The inside of a four-necked glass flask having an internal volume of 3 Lwas substituted with nitrogen, and 2 g of the organotin/phosphoric acidester condensate obtained in Synthesis Example 2 (example of catalystpreparation), 75 g of propylene carbonate glycidyl ether having a watercontent adjusted to 10 ppm or below, and 1,000 g of n-hexane as asolvent were charged. While monitoring the rate of polymerization ofpropylene carbonate glycidyl ether by means of a gas chromatography, 175g of ethylene oxide was added gradually. The polymerization reaction wasterminated with methanol. After recovering the polymer by decantation,it was dried at 40° C. under normal pressure for 24 hours, and furtherat 45° C. under reduced pressure for 10 hours to give 350 g of thepolymer. This copolymer had a glass transition temperature of −45° C., aweight-average molecular weight of 1,100,000, and a heat of fusion of 41J/g. The composition of this polymer in terms of monomers was 90% by molof ethylene oxide and 10% by mol of propylene carbonate glycidyl etheras determined by its ¹H NMR spectrum.

EXAMPLE 2

One gram of the copolymer obtained in Example 1 was dissolved in 20 mlof tetrahydrofuran, and a solution of lithium perchlorate intetrahydrofuran was mixed therewith so as to give a molar ratio (thenumber of moles of the electrolyte salt compound/the total number ofmoles of ether oxygen atom in the polyether copolymer) of 0.08. Thismixture liquid was cast on a mold made of polytetrafluoroethylene, anddried thoroughly to give a film. The electric conductivity δ of the filmwas determined by the alternating current method described above. Theelectric conductivity of the solid electrolyte was 1.5×10⁻⁴ S/cm at 40°C.

EXAMPLE 3

One gram of the copolymer obtained in Example 1 was dissolved in 20 mlof acetonitrile, and a solution of lithium bistrifluoromethanesufonylimide (hereinafter referred to as LiTFSI) in acetonitrile wasmixed therewith so as to give a molar ratio (the number of moles ofLiTFSI/the total number of moles of ether oxygen atom in the polyethercopolymer) of 0.05. This mixture was cast on a mold made ofpolytetrafluoroethylene, and dried thoroughly to give a film. Theproperties of this film were determined as described in Example 2. Theelectric conductivity of the solid electrolyte was 5.2×10⁻⁴ S/cm at 40°C.

EXAMPLE 4

A secondary cell was constructed using the solid polymer electrolyteobtained in Example 2 as the electrolyte, a lithium metal foil as theanode and lithium cobaltate (LiCoO₂) as the cathode. The size of thesolid polymer electrolyte was 10 mm×10 mm×0.2 mm. The size of thelithium foil was 10 mm×10 mm×0.1 mm. Lithium cobaltate was prepared bymixing predetermined amounts of powdery lithium carbonate and cobaltcarbonate and calcinating the mixture at 900° C. for 5 hours, which wasthen crushed. To 85 parts by weight of lithium cobaltate thus obtained,12 parts by weight of acetylene black and 3 parts by weight of the solidpolymer electrolyte obtained in Example 2 were added, mixed by rolls,and then press molded by applying a pressure of 300 kgW/cm² to give acathode of the cell having a size of 10 mm×10 mm×2 mm.

The solid polymer electrolyte obtained in Example 2 was sandwichedbetween the lithium metal foil and the lithium cobaltate plate, and thecharge-discharge characteristics of the cell were studied at 25° C.while applying a pressure of 10 kgW/cm² so as to tightly join theinterfaces. The discharging current was 0.1 mA/cm² at the initialterminal voltage of 3.8V, and the cell could be charged at 0.1 mA/cm².Since the cell of this Example can be easily manufactured in a thinshape, such cells are lightweight and have a high capacity.

EXAMPLE 5

The inside of a four-necked glass flask having an internal volume of 3 Lwas substituted with nitrogen, and 2 g of the organotin/phosphoric acidester condensate obtained in Synthesis Example 2 (the example ofcatalyst preparation), 125 g of propylene carbonate glycidyl etherhaving a water content adjusted to 10 ppm or below, 8 g of allylglycidyl ether and 1,000 g of n-hexane as a solvent were charged. Whilemonitoring the rate of polymerization of propylene carbonate glycidylether by means of a gas chromatography, 125 g of ethylene oxide wasadded gradually. The polymerization reaction was terminated withmethanol. After recovering the polymer by decantation, it was dried at40° C. under normal pressure for 24 hours, and further at 45° C. underreduced pressure for 10 hours to give 235 g of the terpolymer. Thispolymer had a glass transition temperature of −41° C., a weight-averagemolecular weight of 850,000 according to the gel permeationchromatography, and a heat of fusion of 25 J/g. The composition of thispolymer in terms of monomers was 81% by mol of ethylene oxide, 17% bymol of propylene carbonate glycidyl ether, and 2% by mol of allylglycidyl ether as determined by its ¹H NMR spectrum.

EXAMPLE 6

One gram of the terpolymer obtained in Example 5 and 0.015 g of acrosslinking agent, dicumyl peroxide, were dissolved in 20 ml ofacetonitrile, and 5 ml of a solution of LiTFSI in tetrahydrofuran wasmixed therewith so as to give a molar ratio, (the number of moles of thesoluble electrolyte salt compound)/(the total number of moles of etheroxygen atom in the polyether copolymer), of 0.05. This mixture was caston a mold made of polytetrafluoroethylene, dried, then heated andcompressed at 160° C. under 20 kg/cm² for 10 minutes to give across-linked film. The properties of the cross-linked film were measuredas described in Example 2. The electric conductivity of the solidelectrolyte was 3.6×10⁻⁴ S/cm at 40° C.

EXAMPLE 7

A secondary cell was constructed using the solid polymer electrolyteobtained in Example 6 as the electrolyte, lithium metal foil as theanode and lithium cobaltate (LiCoO₂) as the cathode. The size of thesolid polymer electrolyte was 10 mm×10 mm×0.2 mm. The size of thelithium foil was 10 mm×10 mm×0.1 mm. Lithium cobaltate was prepared bymixing predetermined amounts of powdery lithium carbonate and cobaltcarbonate and calcinating the mixture at 900° C. for 5 hours, which wasthen crushed. To 85 parts by weight of lithium cobaltate thus obtained,12 parts by weight of acetylene black and 3 parts by weight of the solidpolymer electrolyte obtained in Example 6 which had been free fromsolvents and had not yet been cross-linked were added, mixed usingrolls, and then press molded by applying a pressure of 300 kgW/cm² togive a cathode of the cell having a size of 10 mm×10 mm×2 mm.

The solid polymer electrolyte obtained in Example 6 which had been freefrom solvents and had not yet been cross-linked was sandwiched betweenthe lithium metal foil and the lithium cobaltate plate, and thecharge-discharge characteristics of the cell were studied at 25° C.while applying a pressure of 10 kgW/cm² so as to tightly join theinterfaces. The discharging current was 0.1 mA/cm² at the initialterminal voltage of 3.8V, and the cell could be charged at 0.1 mA/cm².Since the cell of this Example can be easily manufactured in a thinshape, such cells are lightweight and have a high capacity.

EXAMPLE 8

One gram of the terpolymer obtained in Example 5 and 0.015 g of acrosslinking agent, dicumyl peroxide, were mixed with 0.5 ml of asolution of LiTFSI in propylene carbonate so as to give a molar ratio,(the number of moles of the soluble electrolyte salt compound)/(thetotal number of moles of ether oxygen atom in the polyether copolymer),of 0.05. This mixture was cast on a mold made ofpolytetrafluoroethylene, then heated and compressed at 160° C. under 20kgW/cm² for 10 minutes to give a gel-type cross-linked film. Theproperties of the gel-type cross-linked film were measured as describedin Example 2. The electric conductivity of the solid electrolyte was1.1×10⁻³ S/cm at 40° C.

EXAMPLE 9

One gram of the terpolymer obtained in Example 5 and 0.015 g of acrosslinking agent, dicumyl peroxide, were mixed with 0.5 ml of asolution of LiTFSI in tetraethylene glycol dimethyl ether so as to givea molar ratio, (the number of moles of the soluble electrolyte saltcompound)/(the total number of moles of ether oxygen atom in thepolyether copolymer), of 0.05. This mixture liquid was cast on a moldmade of polytetrafluoroethylene, then heated and compressed at 160° C.under 20 kgW/cm² for 10 minutes to give a gel-type cross-linked film.The properties of the gel-type cross-linked film were measured asdescribed in Example 2. The electric conductivity of the solidelectrolyte was 9.8×10⁻⁴ S/cm at 40° C.

EXAMPLE 10

A secondary cell was constructed using the gel-type solid polymerelectrolyte obtained in Example 8 as the electrolyte, lithium metal foilas the anode and lithium cobaltate (LiCoO₂) as the cathode. The size ofthe solid polymer electrolyte was 10 mm×10 mm×0.2 mm. The size of thelithium foil was 10 mm×10 mm×0.1 mm. Lithium cobaltate was prepared bymixing predetermined amounts of powdery lithium carbonate and cobaltcarbonate and calcinating the mixture at 900° C. for 5 hours, which wasthen crushed. To 85 parts by weight of lithium cobaltate thus obtained,12 parts by weight of acetylene black and 3 parts by weight of the solidpolymer electrolyte obtained in Example 6 which had been free fromsolvents and had not yet been cross-linked were added, mixed usingrolls, and then press molded by applying a pressure of 300 kgW/cm² togive a cathode of the cell having a size of 10 mm×10 mm×2 mm.

The solid polymer electrolyte obtained in Example 8 was sandwichedbetween the lithium metal foil and the lithium cobaltate plate, and thecharge-discharge characteristics of the cell were studied at 25° C.while applying a pressure of 10 kgW/cm² so as to tightly join theinterfaces. The discharging current was 0.1 mA/cm² at the initialterminal voltage of 3.8V, and the cell could be charged at 0.1 mA/cm².Since the cell of this Example can be easily manufactured in a thinshape, such cells are lightweight and have a high capacity.

EXAMPLE 11

A secondary cell was constructed using the gel-type solid polymerelectrolyte obtained in Example 9 as the electrolyte, lithium metal foilas the anode and lithium cobaltate (LiCoO₂) as the cathode. The size ofthe solid polymer electrolyte was 10 mm×10 mm×0.2 mm. The size of thelithium foil was 10 mm×10 mm×0.1 mm. Lithium cobaltate was prepared bymixing predetermined amounts of powdery lithium carbonate and cobaltcarbonate and calcinating the mixture at 900° C. for 5 hours, which wasthen crushed. To 85 parts by weight of lithium cobaltate thus obtained,12 parts by weight of acetylene black and 3 parts by weight of the solidpolymer electrolyte obtained in Example 6 which had been free fromsolvents and had not yet been cross-linked were added, mixed by rolls,and then press molded by applying a pressure of 300 kgW/cm² to give acathode of the cell having a size of 10 mm×10 mm×2 mm.

The solid polymer electrolyte obtained in Example 9 was sandwichedbetween the lithium metal foil and the lithium cobaltate plate, and thecharge-discharge characteristics of the cell were studied at 25° C.while applying a pressure of 10 kgW/cm² so as to tightly join theinterfaces. The discharging current was 0.1 mA/cm² at the initialterminal voltage of 3.8V, and the cell could be charged at 0.1 mA/cm².Since the cell of this Example can be easily manufactured in a thinshape, such cells are lightweight and have a high capacity.

EFFECTS OF THE INVENTION

The solid polymer electrolytes of the present invention are excellent intheir processability, formability, mechanical strength, flexibility,heat resistance and other properties, and have remarkably improved ionicconductivities. They have various applications such as for an electronicapparatus, for example, solid batteries (particularly secondarybatteries), high capacitance capacitors, display devices, e.g. anelectrochromic display, as well as applications as antistatic agents forrubber or plastic materials or as electrically controlling materials.

What is claimed is:
 1. A polyether copolymer having a weight-averagemolecular weight of 10⁴ to 10⁷ which may optionally be cross-linked andwhich comprises: (A) 1 to 99% by mol of a repeating unit derived from amonomer represented by the formula (I):

 wherein R¹ represents a divalent organic group selected from the groupconsisting of —CH₂—O—(CHA¹—CHA²—O)_(n)—CH₂—, —CH₂—O—(CH₂)_(n)—,—CH₂—O—(O)C—(CH₂)_(n)—, —(CH₂)_(m)—CO₂—(CH₂)_(n)—, and—(CH₂)_(m)—O—CO₂—(CH₂)_(n)—, wherein A¹ and A² each is hydrogen or amethyl group, n is a number of from 0 to 12 and m is a number of from 0to 6, (B) 99 to 1% by mol of a repeating unit derived from a monomerrepresented by the formula (II):

 and (C) 0 to 15% by mol of a repeating unit derived from a monomerhaving one epoxy group and at least one reactive functional group. 2.The polyether copolymer of claim 1, wherein the group R¹ in the formula(I) is —CH₂—O—(CHA¹—CHA²—O)_(n)—CH₂—, —CH₂—O—(CH₂)_(n)—, or—CH₂—O—(O)C—(CH₂)_(n)—, wherein A¹ and A² each is hydrogen or a methylgroup, and n is a number of from 0 to
 6. 3. The polyether copolymer ofclaim 1, wherein the reactive functional group in the repeating unit (C)is (a) a reactive silicon group, (b) an epoxy group, (c) anethylenically unsaturated group, or (d) a halogen atom.
 4. The polyethercopolymer of claim 3, wherein the monomer having a reactive silicongroup which constitutes the repeating unit (C) is3-glycidoxypropyltrimethoxysilane,3-glycidoxypropylmethyldimethoxysilane,4-(1,2-epoxy)butyltrimethoxysilane, or2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.
 5. The polyether copolymerof claim 3, wherein the monomer having two epoxy groups whichconstitutes the repeating unit (C) is2,3-epoxypropyl-2′,3′-epoxy-2′-methylpropyl ether or ethyleneglycol-2,3-epoxypropyl-2′,3′-epoxy-2′-methylpropyl ether.
 6. Thepolyether copolymer of claim 3, wherein the monomer having anethylenically unsaturated group which constitutes the repeating unit (C)is allyl glycidyl ether, 4-vinylcyclohexyl glycidyl ether, α-terpinylglycidyl ether, cyclohexenylmethyl glycidyl ether, p-vinylbenzylglycidyl ether, allylphenyl glycidyl ether, vinlyl glycidyl ether,3,4-epoxy-1-butene, 3,4-epoxy-1-pentene, 4,5-epoxy-2-pentene,1,2-epoxy-5,9-cyclododecadiene, 3,4-epoxy-1-vinylcyclohexene,1,2-epoxy-5-cyclooctene, glycidyl acrylate, glycidyl methacrylate,glycidyl sorbate, glycidyl cinnamate, glycidyl crotonate orglycidyl-4-hexenoate.
 7. The polyether copolymer of claim 3, wherein themonomer having a halogen atom which constitutes the repeating unit (C)is epibromohydrin or epiiodohydrin.
 8. The polyether copolymer of claim1, which comprises 10-95% by mol of the repeating unit (A), 90-5% by molof the repeating unit (B), and 0-10% by mol of the repeating unit (C).9. A solid polymer electrolyte which comprises: (1) a polyethercopolymer of claim 1, (2) an electrolyte salt compound, and, (3)optionally present, a plasticizer selected from aprotic organic solventsand esters, ethers or metal salts of linear or branched polyalkyleneglycols having number-average molecular weights of 200 to 5,000 or metalsalts of said esters or ethers.
 10. The solid polymer electrolyte ofclaim 9, wherein the electrolyte salt compound (2) comprises a cationselected from metal cations, ammonium ion, amidinium ion, and guanidiumion, and an anion selected from chloride ion, bromide ion, iodide ion,perchlorate ion, thiocyanate ion, tetrafluoroborate ion, nitrate ion,AsF₆ ⁻, PF₆ ⁻, stearylsulfonate ion, octylsulfonate ion,dodecylbenzenesulfonate ion, naphthalenesulfonate ion,dodecylnaphthalenesulfonate ion, 7,7,8,8-tetracyano-p-quinodimethaneion, X¹SO₃ ⁻, [(X¹SO₂)(X²SO₂)N]⁻, [(X¹SO₂)(X²SO₂)(X³SO₂)C]⁻, and[(X¹SO₂)(X²SO₂)YC]⁻, wherein X¹, X², X³ and Y each is anelectron-attractive group.
 11. The solid polymer electrolyte of claim 9,wherein X¹, X² and X³ each is independently a perfluoroalkyl grouphaving 1-6 carbon atoms or a perfluoroaryl group having 6-18 carbonatoms, and Y is a nitro, nitroso, carbonyl, carboxyl, or cyano group.12. The solid polymer electrolyte of claim 9, wherein the metal cationis the cation of a metal selected from Li, Na, K, Rb, Cs, Mg, Ca, Ba,Mn, Fe, Co, Ni, Cu, Zn, and Ag.
 13. The solid polymer electrolyte ofclaim 9, wherein the aprotic organic solvent is an aprotic organicsolvent selected from ethers or esters.
 14. The solid polymerelectrolyte of claim 9, wherein the aprotic organic solvent is anorganic solvent selected from propylene carbonate, γ-butyrolactone,butylene carbonate, 3-methyl-2-oxazolidone, triethylene glycol dimethylether, triethylene glycol diethyl ether, tetraethylene glycol dimethylether, and tetraethylene glycol diethyl ether.
 15. The solid polymerelectrolyte of claim 9, wherein the polyalkylene glycol is polyethyleneglycol or polypropylene glycol.
 16. The solid polymer electrolyte ofclaim 9, wherein the derivative of polyalkylene glycol is an etherderivative or an ester derivative.
 17. The solid polymer electrolyte ofclaim 9, wherein the metal salt of polyalkylene glycol is any one of asodium salt, a lithium salt, and a dialkylaluminum salt.
 18. A batterycomprising a solid polymer electrolyte of claim 9, a cathode and ananode.